Another newbie question. This time related to brake fluid. I have never changed brake fluid and have 3 Toys (92 4x4/170K, 01 Hihglander/64K and 01 Rav4/35K). First, when should the brake fluid be changed? Second, what is the best method? bleeding? Thanks guys! This is one awesome site!

I use to change the brake fluid when I changed pads or shoes. But But after 8 years the original pads and shoes are still good so I changed the fluid anyway. Needless to say it was nasty . From what I understand you should change the brake fluid every 2 years. This is especially true if you have abs brakes. They are sensitive to clean fluid. If you don't keep the fluid clean you can really mess up the abs system. And it costs a FORTUNE to fix. So it's cheaper to change the fluid every 2 years. My brother in law showed me how to do it by bleeding each wheel cylinder until clear fluid came out. It was a 2 person job. 1 in the car pressing on the pedal and 1 operating the bleeder screws. As long as you you don't let the master cylinder go dry while bleeding you can start on any wheel. But if the master cylinder goes dry or gets air in it then you have to start bleeding on the wheel furthest from the master cylinder and work to the closest wheel. My small Ford Contour used slightly more than a quart of brake fluid to do a complete change. Also be aware that if you haven't opened the bleeder screws on the wheel cylinders in a long time they may be rusted on and possibly break off when trying to open them. Perhaps you should soak them with a penetrating spray first. Also if you haven't changed the fluid in a long time bleeding them this way you can possibly mess up the seals in the master cylinder. Though I had no problem with mine after 8 years without bleeding.

What does your owner's manual say? Brake fluid doesn't last forever, and neither does rubber. For most cars, the brake fluid is replaced soon enough through rebuilding the calipers before the rubber parts go bad. I ran a 92 Grand Am with ABS 180K in 10 years and never changed the fluid as such, and never had any brake problems. I did rebuild the calipers and wheel cylinders, replacing most of the fluid. Also, get something in the way of a book, and follow the directions exactly on bleeding. I prefer real shop manuals to Chilton's, see www.factorymanuals.com. Changing brake fluid is mostly for hobbyists lacking useful things to do. Bleeding may or may not remove the the old fluid from the bottom of the bore where the damage occurs. It also does nothing for the critical area between the O-rings and the boots in a caliper.

Brake fluid is hygroscopic. It should be replaced every two years. I a mild climate without high humidity and no low temps, you might get away with 3 years. If water builds up in the brake system you will get corrosion, you will damage your ABS controller, and most of all, in an emergency situation, your brake fluid (actually, the water in it) will start boiling and you will not have the braking power you need.

I've always replaced brake fluid at a maximum of 3 years and have never had a single problem with calipers, wheel cylinders, master cylinders or lines. This includes a 19 year old VW with over 150k miles and a 13 year old Ford pickup with over 200k miles. My feeling, anyway, is that the water causes corrosion which affects the seals. From my experience with this, master cylinders, lines, wheel cylinders and calipers should be "life of the car" components as long as the fluid is kept clean. My VW maintenance schedule shows brake fluid changes at 2 years. They don't bother even talking about coolant and gearbox oil, which obviously need to be changed periodically. So if they put it in the book it means something IMO.

I have no connection with Motive other than being a very happy customer. This tool is definitely worth the money (doesn't cost much) and makes it a quick one person job with easy good results. You can build one yourself out of a plant sprayer too.

Every 2 years is a good goal. Not more than 3. Brake fluid is hydroscopic. If you go off roading and drive through creeks, you may have to change b. fluid more often. Agin due to water contamination. I like Haynes manual better than the Chilton. The factory service manual is always better, but much more expensive. Look for a one man bleeder system such as Vacula or Phoenix. Go on the Toyota lists for more specific details.

If your taking the car to the track, road course, or racing on the weekends...

Its generally recommended to change at least once during the season, with a minimum of once per year. (Usually two times on light duty racing, and any where from every other race to every race if its heavy).

There are a variety of applications which make bleeding the brakes much easier then with default equipment, like speedbleeders or power bleeders.

Bleeding your brakes also firms up your brake pedal, depending on the type of braking feel you want.

With the right setup, it takes less time to bleed your brakes then it does to get the car on jacks and the wheels off...

Labman, I've been following your advice on brake fluid for some time now. Some of what you say makes sense, but not all of it. Your advice holds water for people that drive 15-20K each year, and renew their brakes every 2-3 years. But for people such as myself that have multiple cars and drive few miles, we need to follow a more regimented maintenance schedule than what the owner's manual recommends (which is sometimes nothing). The past couple of years I've put no more than 3K per year on any of my vehicles. I need to protect these braking systems from corrosion and I don't want to wait until the pads are worn or the caliper siezes.

I do like your advice of buttering healthy caliper bore and piston surfaces with silicone grease to prevent corrosion at the critical seal surface. I'll try it on my next brake job. I'd like somebody else to verify this practise.

quote:Originally posted by labman: Maybe that is all the longer the Eurospec stuff is good for. I never heard of any problems due to not changing brake fluid in a For or GM product.

My '85 VW uses standard DOT3, and my '97 VW uses DOT4. Same stuff you can go to Napa and buy, and same as I put in our Dodge, Ford and MG.

And it does improve pedal feel, believe it or not. I would never have believed it if I hadn't felt it the first time. I don't know how, because the water is just as incompressible as the glycol, but it does.

quote:Originally posted by gatesj: My '85 VW uses standard DOT3, and my '97 VW uses DOT4. Same stuff you can go to Napa and buy, and same as I put in our Dodge, Ford and MG.

And it does improve pedal feel, believe it or not. I would never have believed it if I hadn't felt it the first time. I don't know how, because the water is just as incompressible as the glycol, but it does.

You get a small amount of air in the hydraulic fluid over time. That's the main reason you feel a difference after you bleed your brakes.

Even a fraction of 1% air makes a big difference in the bulk modulus (stiffness) of hydraulic or brake fluid.

Flush your brake fluid once every 2 years and you are unlikely to ever need to rebuild a master cylinder, wheel cylinder or caliper. Leave the fluid untouched and you can count on eventual corrosion. For some reason almost all european brands spec every 24 month fluid changes while GM and Ford say nothing on the subject. This is not due to any weakness of the euro products, but rather is because they are telling it like it is.

Anyone who says they "haven't seen a problem" from old brake fluid simply has not looked closely enough. Tear down and inspect the components of a ten year old brake system with it's original fluid and you will find corrosion.

The easiest way I've found to flush multiple cars at a reasonable cost is with the Motive Products flush system. It costs around $50 configured for a single type of vehicle, more if you get multiple adapters. $100 sets you up for 99% of the cars on the road.

I used to use Castrol LMA fluid as an everyday high quality brake fluid. LMA is still around and is still good stuff, but it is not as widely stocked as it used to be.

Lately I've switched to Valvoline Synpower brake fluid as it is a fluid with much better than generic DOT3 specs, is readily available and is reasonably priced. Our local AutoZone carries it at about $2 more per quart than the generic DOT 3 stuff. Figure on one quart per vehicle for a complete system flush. You want to run fluid through until it comes out as clean as the new stuff going in. Used brake fluid gets darker as it absorbs moisture and contaminants.